An actuator with a top plate having at least one duct opening, in particular for an electrical contact pin, is known from DE 199 40 347 A1. A plastic cover contains contact pins.
The design of an actuator for injection valves is known from DE 198 18 068 A1. There, a piezostack is bounded at its ends by a top plate and a base plate and surrounded by a cylindrical tube spring which is welded at its end openings to in each case the base plate or top plate.